Magnetic combination door lock

ABSTRACT

A biased tumbler-lever lock and magnetic key combination wherein the magnetic fields on the key cause the rotation of biased tumbler-levers about a pivot point in the lock to a particular position so as to free a bolt in the lock. The number of degrees of angular rotation of each tumbler-lever arm is determined by the magnetic field strength and the biasing strength. The tumbler-lever arms include an engagement mechanism having a normal engagement finger and an override engagement finger. The biasing force keeps the engagement mechanism of the tumbler-lever in the normal (locked) position when the magnetic means in the key is absent. Excessive rotation of the tumbler-lever, caused by excessive magnetic field strength re-engages the engagement mechanism to prevent release of th bolt. Insufficient rotation of the tumbler-lever prevents disengagement of the engagement mechanism and the bolt.

United States Patent Csurgay 1 Sept. 24, 1974 MAGNETIC COMBINATION DOOR LOCK [57] ABSTRACT [76] Inventor: Gregory N. Csurgay, 3320 NE. A biased tumbler-lever lock and magnetic key combil8th Ter., Fort Lauderdale, Fla. nation wherein the magnetic fields on the key cause 33305 the rotation of biased tumbler-levers about a pivot point in the lock to a particular position so as to free [22] Flled' 1972 a bolt in the lock. The number of degrees of angular [21] Appl. No.: 317,755 rotation of each tumbler-lever arm is determined by the magnetic field strength and the biasing strength.

The tumbler-lever arms include an engagement mech- CCll. anism having a normal engagement finger and an [58] d "70/276 413 override engagement finger. The biasing force keeps le 0 the engagement mechanism of the tumbler-lever in the normal (locked) position when the magnetic means in [56] References cued the key is absent. Excessive rotation of the tumbler- UNITED STATES PATENTS lever, caused by excessive magnetic field strength re- 3,416,335 12/1968 Barney 70/276 X engages the engagement mechanism to prevent release 3,744,833 7/1973 Berducone of th bolt. Insufficient rotation of the tumbler-lever prevents disengagement of the engagement mechanism and the bolt.

3 Claims, 4 Drawing Figures u I: IIIIIIII. a TIIIIIII PATENTEDsmmsu SII'IIEOF4 FIG. 4'

MAGNETIC COMBINATION DOOR LOCK BACKGROUND OF THE INVENTION In the past, magnetic locks were devised to provide the lock operator with a lock that was easier to operate and more difficult to pick" than conventional locks. Such magnetic locks typically employed pin tumblers sliding in radial bores that could be unlocked with any key whose magnetic field strength was in excess of the minimum strength required to free the bolt.

The present invention employs a bolt engagement mechanism that requires the magnetic field strength of the key to be within certain adjustable limits in order to unlock the bolt; as such, it maintains the ease of operation and presents a more difficult task for one who would attempt to pick it.

SUMMARY OF THE INVENTION The present invention includes a magnetic key and biased tumbler-lever lock. The magnetic key employs one or more magnetic fields, each of which has a varying magnitude and polarity along the length of the key. Each magnetic field attracts or repells a particular tumbler-lever. The lock includes a bolt, at least one tumbler-lever, and biasing means for each magnetic field on the key. Each tumbler-lever includes an engaging mechanism having a normal engagement finger and an override engagement finger that engages the bolt. The

engaging mechanism is rotatable back and forth through an arc. An adjustable biasing force is positioned along one of the arms of the tumbler-lever. The engaging mechanism, in the form of a tuning fork with an inwardly pointing bolt engaging finger at each distal end of the U-shaped portion. Biasing means are connected to each engaging mechanism. The biasing means holds the first finger, i.e., the normal engagement finger, in contact with the bolt to hold it in the locked position. The magnetic force generated by the key is positioned to act upon the tumbler-lever arm causing the tumbler-lever to rotate until equilibrium is achieved between the bias force and the magnetic key force to disengage the first finger from the bolt. If the key in the lock is the correct key, the accurate rotation of the tumbler-lever will be the precise number of degrees required to disengage the bolt. Any magnetic key force of less magnitude will cause the rotation of the tumbler-lever to stop short of the disengagement point. Any magnitude key force of greater magnitude will cause rotation of the tumbler-lever to pass by the disengagement point to lock the override engagement finger in contact with the bolt.

In accordance with these and other objects which will 'be apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of one tumbler-lever with the proper key in the lock.

FIG. 2 is a front view of one tumbler-lever with a key of insufficient strength in the lock.

FIG. 3 is a front view of one tumbler-lever with a key greater strength in the lock.

FIG. 4 is an isometric view of a plurality of tumblerlevers.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings and particularly to 5 FIG. 1, the biased tumbler-lever lock, generally shown by numeral 8, includes key 29 with magnetic portion 29 in key slot 11, key slot 11 is shaped so as to admit a key in only position, a tumbler-lever, shown generally by number 10, in an opened position with the engagement member 28, and bolt 25. The engagement member 28 is connected to the distal arm 14 of tumblerlever and includes a lock securing means including the first finger 6 and second finger 7. The tumbler-lever 10 rotates about pivot point 18. In response to an imbalance between the force of attraction of magnets 19 and 20, and magnets 22 and 23, and the force exerted by the magnetic key 29 against magnet 12; the tumblerlever rotates about pivot point 18 from the locked position of FIG. 2 to the position shown in FIG. 1 to provide a lock securing actuating means. If the repulsive force of the key 29 is too great the tumbler-arm would move to the relocked position of FIG. 3.

By turning screws 21 and 24 the magnetic bias force of magnets 19, 20 and 22, 23 may be adjusted to vary the gaps 26 and 27, as such the limits of the magnetic field strength of the key 29, which will allow the lock to be opened may be varied.

FIG. 1 shows a key 29 with a magnetic field of proper polarity and magnitude in the key slot 11, the magnetic field of the key is positioned opposite the magnet 12 on the proximal arm 13 of tumbler-lever 10. The magnetic field on the key 29 exerts a force on the tumbler-lever l0. Tumbler-lever 10 has rotated above pivot point 18 to a new equilibrium position with the forces exerted on the distal arm 14 by bias means 30 exactly balanced by the force exerted on the proximal arm 13 by the magnetic field on key 29. In this position, the fingers 6 and 7 of engagement member 28 are clear of slot in bolt 25.

FIG. 2 shows the invention as it would be if no key were placed in the lock or if a key of proper polarity but insufficient strength were placed in the lock.

I claim:

1. In a lock and magnetic key combination with a key having a magnetic means creating at least one magnetic field in a region of its body wherein the improvement 45 comprises:

lock securing means; at least one tumbler-means with a magnet on its proximal end and having a lock securing actuating means, said tumbler-means operating in at least three modes, the two extreme modes of said tumbler-means actuate the lock securing engaging means in a secured position;

biasing means operating on said tumbler-means; and

from said first member. 

1. In a lock and magnetic key combination with a key having a magnetic means creating at least one magnetic field in a region of its body wherein the improvement comprises: lock securing means; at least one tumbler-means with a magnet on its proximal end and having a lock securing actuating means, said tumbler-means operating in at least three modes, the two extreme modes of said tumbler-means actuate the lock securing engaging means in a secured position; biasing means operating on said tumbler-means; and a key receptacle for positioning the field of the key in relation to the tumbler-means so that magnetic forces move said tumbler-means into equilibrium mode between the two extreme modes and disables the lock securing engaging means.
 2. A device as set forth in claim 1 wherein said biasing comprises: two pairs of magnets with the first magnet from each pair positioned on said tumbler means; the second magnet from each pair secured opposite said first member.
 3. A device as set forth in claim 2 wherein said second member is adjustably moveable toward and away from said first member. 